<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%--在springMvc中放行EL--%>
<%@ page isELIgnored="false" %>
<html>
<body>
<h2>Hello World!</h2>
</body>
    index jsp<br>
    username:${username}
    key:${key}
    ${sessionScope.get("sessionName")}
</html>
